Role of Saline Water in Removal of Heavy Elements from Industrial Wastewaters

Flocculation processes during estuarine mixing can reduce the elemental concentrations of river water. In the present investigation, natural flocculation processes concept is used to reduce the elemental contents of industrial wastewater. For this purpose, various amounts of saline water were added to an artificial industrial wastewater with known concentrations of heavy metals. The results of investigation show that in the salinity of 0.9‰, percentage of elemental flocculation occurs in the order of: Ni (95.4%) > Pb (87.6%) > Zn (85%) > Mn (56.25%) > Cu (14.4%). Flocculation of Cu is insignificant at lower salinities. Though higher removal of heavy metals is obtained at greater salinities but due to the environmental limitations, we propose salinity of 0.9‰. Use of seawater to flocculate heavy metals can greatly reduce the costs associated with the purification of wastewater treatment.